/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/* Copyright (c) 1988 AT&T */
/* All Rights Reserved */
/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
/*LINTLIBRARY*/
void
_des_decrypt1(char *block, char *L, char *IP, char *R, char *preS, char *E, char KS[][48], char S[][64], char *f, char *tempL, char *P, char *FP)
{
/* EXPORT DELETE START */
int i, ii;
int t, j, k;
char t2;
/*
* First, permute the bits in the input
*/
for (j = 0; j < 64; j++)
/*
* Perform a decryption operation 16 times.
*/
i = 15-ii;
/*
* Save the R array,
* which will be the new L.
*/
for (j = 0; j < 32; j++)
tempL[j] = R[j];
/*
* Expand R to 48 bits using the E selector;
* exclusive-or with the current key bits.
*/
for (j = 0; j < 48; j++)
/*
* The pre-select bits are now considered
* in 8 groups of 6 bits each.
* The 8 selection functions map these
* 6-bit quantities into 4-bit quantities
* and the results permuted
* to make an f(R, K).
* The indexing into the selection functions
* is peculiar; it could be simplified by
* rewriting the tables.
*/
for (j = 0; j < 8; j++) {
t = 6*j;
k = S[j][(preS[t+0]<<5)+
(preS[t+4]<<0)+
t = 4*j;
f[t+0] = (k>>3)&01;
f[t+1] = (k>>2)&01;
f[t+2] = (k>>1)&01;
f[t+3] = (k>>0)&01;
}
/*
* The new R is L ^ f(R, K).
* The f here has to be permuted first, though.
*/
for (j = 0; j < 32; j++)
R[j] = L[j] ^ f[P[j]-1];
/*
* Finally, the new L (the original R)
* is copied back.
*/
for (j = 0; j < 32; j++)
L[j] = tempL[j];
}
/*
* The output L and R are reversed.
*/
for (j = 0; j < 32; j++) {
t2 = L[j];
L[j] = R[j];
R[j] = t2;
}
/*
* The final output
* gets the inverse permutation of the very original.
*/
for (j = 0; j < 64; j++)
/* EXPORT DELETE END */
}